Woven fabrics formed of fibrous yarns have long been used to provide a decorative and protective cover to furniture items. The upholstery fabric typically covers cushions and the like which are normally subject to abrasive wear and repeated stresses arising from use of the furniture. For example, stress and wear are often caused by compression of fabric covered cushions by persons seated thereon. Seams formed by sewing multiple pieces of the upholstery fabric together must also resist separation after repeated stresses. Thus, to insure satisfactory performance, an upholstery fabric must have good dimensional stability and strength characteristics to withstand use in furniture applications.
To present satisfactory dimensional stability, single layer woven upholstery fabrics used in furniture applications such as sofas, chairs and the like must be relatively heavy fabrics. Consequently, such single layer upholstery fabrics are relatively expensive to manufacture, as fabrics meeting the above requirements are usually densely woven and have a high number of picks per unit area.
To reduce the expense associated with heavy upholstery fabrics, it has been common to apply a backing to the underside of the upholstery fabric to improve the dimensional stability of the fabric. In so doing, the weight per square yard of the woven upholstery fabric may be reduced, thereby resulting in considerable cost savings.
The most commonly used backing is a latex coating which is applied to the underside of the woven fabric. The latex is applied in liquid form to the fabric and is allowed to dry, thereby bonding to the fabric. It has been found that this approach interlocks the fibers in the woven upholstery fabric, thereby enhancing the dimensional stability of the woven fabric.
Application of a latex backing permits use of an upholstery fabric having a relatively lighter weight than could otherwise be used. A fabric having a latex backing often has a looser weave than a single layer fabric, thereby resulting in significant cost savings.
Although the latex backed fabrics as discussed above may exhibit good dimensional stability, they are also usually substantially stiffer than fabrics which do not have a latex backing. The stiffness of the fabric is also referred to as its hand. A fabric having a good hand is relatively flexible, whereas a stiffer fabric is said to have a poor hand.
The stiffness, or hand, of a fabric is often quite significant in many applications. For example, stiffness is frequently of concern when upholstery fabric is applied to a furniture article. A fabric which is too stiff may be difficult for the upholsterer to use, as the stiffened fabric may not conform adequately to curves, bends and the like which are formed into the furniture frame or cushions. Such problems often result from the use of latex backed fabrics. The stiffness of a latex backed upholstery fabric may also be noticeable to persons seated on the upholstered furniture.
In addition to problems relating to increased stiffness, the use of a latex coating as a fabric backing also often fails to solve adequately the strength problems, including seam slippage, associated with use of lighter weight woven fabrics. Moreover, latex is difficult to handle in a manufacturing environment, as the latex must be applied to the fabric in liquid form. Liquid latex must be handled with care for health and environmental reasons.
Another drawback of using latex as a fabric backing is that the latex may not be applied to the full width of the fabric. For example, after the fabric has been coated, clips are used to engage the edges of the fabric to convey it through a tenter frame for drying the latex coating. Because the clips must engage an area of up to about two inches wide along each edge of the fabric, the edges of the fabric cannot be coated with the latex so that the edges will be dry for handling by the clips. The uncoated edges cannot be used as finished upholstery fabric and must therefore be cut away from the coated fabric.
In many applications, the fabric destined to be coated is initially woven in a width of 54 inches. After the fabric is coated with latex and the unusable uncoated edges removed, however, the resultant fabric may be only 50 inches wide. As may be readily seen, this practice wastes a significant amount of the woven fabric and therefore increases the cost of production.
Other prior art techniques for producing multilayered fabrics having a desired dimensional stability are shown in U.S. Pat. No. 4,159,360 to Kim and U.S. Pat. No. 4,172,170 to Foye. The Foye '170 patent shows a woven upholstery fabric attached to a nonwoven scrim. Fibers are needle punched from the woven layer through the nonwoven scrim after which a latex coating is applied which adheres to the nonwoven backing and the needle punched fibers. Thus, the composite fabric shown in the Foye '170 patent relies on a latex coating to retain its integrity, much the same as any latex backed fabric.
The stabilized fabric shown in the Kim '360 patent has a woven, knitted or tufted fabric layer which is needle punched and bonded to a backing layer of nonwoven fibers by an intermediate layer of thermoplastic material. Inclusion of a third layer of thermoplastic material within the woven and nonwoven fibrous layers increases the cost and complexity of manufacturing the multilayered fabric.
In light of the aforementioned deficiencies, it is an object of the present invention to provide a fabric having the desired dimensional stability without the presence of a latex backing which is normally present thereon. Another object of the present invention is to provide a multilayered upholstery fabric having the desired flexibility or hand and the desired dimensional stability. Yet another object of the present invention is to provide a method for producing a fabric having the desired hand and dimensional stability without the application of a latex backing. A further object of the present invention is to provide an apparatus for producing an upholstery fabric having the desired hand and dimensional stability without the use of a latex backing. Another object of the present invention is to provide a dimensionally stabilized fabric which may be manufactured without cutting away the edges of the fabric. A still further object of the present invention is to provide a process for producing a dimensionally stabilized fabric without the use of environmentally hazardous and difficult to handle liquids.